A conventional gas turbine engine includes multiple rows of compressor blades, multiple rows of rotating turbine blades and a rotating shaft. The turbine blades are designed to convert the hot working gas of the gas turbine engine into rotational energy of the shaft within a turbine section of the engine. Each turbine blade comprises a radially extending outer wall, defining an airfoil shape, and a blade tip. The turbine blades are typically formed of a superalloy material, such as a nickel-based superalloy material. An internal cavity is formed by the outer wall and has a radially outer end that is closed by a tip cap that is typically surrounded by a squealer structure. A cooling fluid is channeled through the internal cavity to cool the outer wall and blade tip.
During normal operation of the gas turbine engine, thermal and mechanical stresses in the turbine blades may result in the formation of defects, such as cracks, in the material of the blades. Gas turbine components, and in particular the turbine blades, are routinely serviced and exchanged when necessary. In order to extend the operational life of the components, whenever possible they are refurbished, after which they may be reused in a gas turbine. Such refurbishment of a turbine blade may, for example, involve replacement of the tip cap and reformation of the squealer structure, such as by build-up welding at the blade tip.